Officials said three similar "hair-cutting incidents" had been reported in the past six weeks. It is still unclear if they were all connected.

Officials also said the nature of the incident is "a pretty unusual activity."

Records show that the three incidents occurred on November 20th at 10 p.m., on the No. 20 bus; December 24th at 8:45 p.m. on the No. 33 bus; and December 31st at 1 p.m., also on the No. 33 bus.

Walter also was cited in December for not having the proper fare to ride a bus.

Oregon law doesn't specifically deal with stealing or gluing a stranger's hair. To address that, prosecutors charged him with third-degree robbery, among other crimes, for forcibly taking something of value from his victims.

As previously discussed, in 2005 Walter was convicted in Texas of burglary with intent to commit a sex crime.

In Oregon, authorities a have dubbed Walter the "TriMet Barber" because he snipped the hair of unsuspecting passengers he sat behind on TriMet buses during the past year.